This week has been a busy one for Carl Icahn, as any of his 94,000-plus Twitter followers can tell you.

On Monday Icahn announced that he had taken a 5.97% stake in Canada's Talisman Energy. On Tuesday, he welcomed the addition of two of his candidates to Nuance Communications' board of directors.

Unsurprisingly, both announcements were made on Icahn's Twitter feed. The tweet has become the 77-year-old's favored means of communicating; last week, he kept followers apprised of his dinner with Apple Inc. CEO Tim Cook, his television appearance and his decision to drop his appraisal bid for his Dell Inc. shares.

Icahn tweeted that he "may have conversations" with Talisman management about "strategic alternatives, board seats, etc." The company is trying to sell some of its assets in Asia, the North Sea and North America, with plans for the slimmed-down company to focus on the latter. In May, CEO Hal Kvisle suggested that the company could be split.

A day later, Icahn said he was "happy to have reached an agreement with Nuance" that will see his son Brett Icahn and David Schechter, a senior analyst at his firm, seated on the company's board. The deal, under which Icahn has agreed to back Nuance's other board candidates and to keep its voting stake in the company below 20%, avoids the proxy fight that Icahn had pledged.

Icahn Enterprises is Nuance's largest shareholder.

"We see numerous, promising growth opportunities for the company," which makes voice-recognition software, Brett Icahn and Schechter said. "We will work with the board and management team to continue enhancing stockholder value."